I configured the ZoiPer free client Advanced / Network / Network Options signaling and media settings both for "EF" and used a packet sniffer to check DSCP values on outbound SIP traffic from the client during a call. The SIP/RTP packet DSCP setting were "0", indicating that the client settings have no effect. Is there another issue that may be causing the ZoiPer traffic not to be marked? This was tested on both Win7Pro and Win8.1Pro installs of the free ZoiPer client.